This invention relates to the field of label augmented, multi-protocol routing of data packets in a network.
In existing data networks, data packets have addresses attached thereto used to route the data packets over xe2x80x9chopsxe2x80x9d between a source and a destination router in the network. These addresses are assigned at each router, indicating the path of the next hop, and the addresses typically contain more information than is needed.
Multi-Protocol Label Switching (MPLS) provides for more efficient data forwarding based on the use of fixed size labels in making forwarding decisions. This mechanism is based on routing topology.
A mechanism and method is described by which Label Switched Paths (LSPs) can be explicitly established using a defined distribution protocol to meet requirements of users and networks. In particular, a negotiative protocol is defined for supporting Label Distribution in Multi-Protocol Label Switching (MPLS). This protocol allows for explicit route label setup, loop-free multicast tree setup, and label value negotiation.
The basic idea is to specify portions of a label which are defined by the upstream neighbor in an adjacent pair of Label Switching Routers (LSRs). The portion of the label which is assigned by the upstream neighbor is defined as a bit mask which indicates those portions of the label which remain to be assigned by the downstream neighbor. If all bits are zero, the label is fully determined by the upstream neighbor, otherwise any bit in the mask is set-able by the downstream neighbor. The range of set-able addresses may be further refined through the use of generic extensions to the protocol.
Multicast services may be optimized as a result of being able to allocate flow-classification labels from the source toward the destination (upstream allocation). Other applications of traditional IP Routing, such as Quality of Service routing, can be greatly augmented by the ability to establish a label switched path across specific routers. Our proposal embodies mechanisms to accomplish these aims.
This invention can be used with any media to be used for MPLS or any other form of label-based multi-protocol routing. As an example, the present invention may be incorporated specifically for IP routing support in access multiplexers or other network components.